The violent, on-going feud within the ranks of one of Australia's most notorious bikie gangs, the Comancheros, has flared again with a Sydney clubhouse ambushed and its members beaten.

Following months of tension, the Herald has been told that senior gang members are preparing for a civil war after the clubhouse of the South Chapter was stormed on Wednesday night.

A source linked to the club said that up to 80 members from three other Comanchero chapters - the East, Wild West and Milperra, were responsible for the raid on the Turrella premises in Sydney's south at 8:30pm.

Wearing all black and armed with guns and torches, the bikies stormed the clubhouse and told the 20 South members meeting inside that their chapter was to be closed down.

The South members were then told they could defect to one of the other chapters or "hand back your colours".

Several of the South members were bashed, the source said, including a veteran Comanchero member and another man who remains in Bankstown Hospital with a broken jaw, nose and ribs.

Police on Thursday said they were investigating the attack on the man but have no information about an incident at Turrella.

Amidst a power struggle within the gang, South commander, Mohammad "Mick" Hijazi, became one of the nation's highest ranking members and was touted as a potential national president.

The Herald revealed in April that the Comancheros had expanded and opened the South chapter which boasted about 40 members.

However in the weeks since, its formation has not sat well with some within the club ranks.

Hijazi left the country for Lebanon shortly after the chapter was set up and as the tension grew.

The source said that Wednesday night's attack was a bid by other senior Comancheros to show their authority over the club.

Hijazi, the source said, was now planning to fly back to Sydney and to "sort it all out".

Police warned about tensions within the Comancheros late last year after junior Comanchero Faalau Pisu was shot dead outside a wedding reception at Canley Vale, in Sydney's south-west, in November.

Two days later another Comanchero, John Devine, 28, the cousin of club president Mark Buddle, was gunned down on a Rhodes street. He dragged himself 500 metres before collapsing in a bloody heap outside the Rhodes Shopping Centre.

Police at the time said both shootings related to an internal crisis within the Comancheros and that they expected more trouble in the future.